The general objective of this study is to grasp the treatment expenses of common diseases by character of medical care institutions. The specific objective is to find out the treatment expenses for selected common diseases by type of medical care institutions and also by level of symptom. A record review method was employed to obtain required information for the analysis of expenses. A total of 40,000 cases treated by 85 medical care institutions were selected by the study team during the period 22 June to 14 July 1988. The 85 medical care institutions were sampled by stratified proportionate random sampling method. The major findings obtained from the information collected by the study team are as follows ; 1) Treatment expenses were composed of physical examination, medication, injection anesthesia, rehabilitation surgical intervention, lab test, X-ray and diagnosis. The highest expenses was for medication, accounted for 36.7% of the total: 13.9%, injection; Lab, tests respectively: 10.5%, physical examination : 8.6% surgical intervention; 7.9% admission : 6.3%, X-ray and diagnosis: 1.5%, rehabilitation. 2) Treatment expenses per case of common diseases were quite different from not only type of medical care institutions, such as university hospital, general hospital, hospital and clinic, but also from level of symptom. 3) Treatment expenses per case for the aged were higher than that of the young. The treatment cases for over 60 years of age accounted for 19.4% of the total, however the proportion of treatment expenses accounted for 23.8% of the total. 4) Duration of treatment and visits for same diseases varied from type of medical cara institutions. Based on these study findings, the following further research should be conducted: (1) Establishment of health care delivery system. (2) Feasibility of the development of health care programme for the aged. (3) Strengthening for primary health care approach.